liambesaw
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Posts posted by liambesaw
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21 minutes ago, oldlady said:
cracking can also occur in flat slabs with deep indentations. picture the typical cookie cutter with a shape that has sharp angles, like the deep notch in heart shaped cutters. if you cut something like this, a rounded dowel or the used pencil eraser that is rounded over, can be pressed into the angle to compress the clay.
Could you compress from inside the cookie cutter instead? Kind of like a hamburger press? Would probably give neater lines with less hassle
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27 minutes ago, neilestrick said:
I ran into a kiln like that once, where the previous repair guy had put a Bartlett controller on a Nabertherm and didn't do it right. I got a nice little shock when I tried to push an element in, even though the controller wasn't actually running. Luckily the teacher at the school had never gotten shocked. This is why two pole relays are used. Switching only one leg, the element won't heat up because the circuit loop isn't closed, but when you touch the element and ground it out you'll get hit.
@jbruce I'm also worried about the extension cord wires. Those wires are only rated for 12-20 amps, depending on the size of the cord. How did you arrive at it being large enough for 4 times the 40 amps? And if the kiln pulls 40 amps, the wires should be rated for 50 amps, which means you should have 6 gauge wire in there.
I think he's using all three conductors in each extension cord as a single conductor
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Interesting, and I assume you mean ground instead of neutral? I'll be direct wiring my kiln so I get to skip all the plug stuff, looks like it will be pretty simple! Can't wait! Gonna get started on running the 50 amp circuit to my kiln this weekend, I'm so stoked. Will probably do a couple firings without the rpi first just to get a feel of what it's capable of, but then I'm making one of these controllers for sure.
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That's a handy tip, thanks @neilestrick
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1 hour ago, JohnnyK said:
Have you tried putting a fan blowing on low to help dry things out a little? I have similar weather conditions here in Citrus Heights, CA and found the fan helps speed up the drying process...
I've used a little space heater, works prettty good but costs a bit to run. I'll keep an eye out for small fan and see if it works just as well, thanks!
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42 minutes ago, Pres said:
Liam are you doing your incising before shaping, that often softens the lines. Nice clean shapes from what I can see.
best,
Pres
Kind of, I do them while shaping with my steel rib. I pull the cylinder and then scrape the slip off and shape the base at the same time, then I will fine tune the shape from inside with a small wood rib. I probably should go back and sharpen them up again after, the line is just the line of slip that the steel rib leaves.
Should have seen me sitting there in my shed trying to figure out how to do it nicely like the ones I mistakenly left like that last time. I like the way glaze breaks over the horizontal line though, it's really nice.
If you were talking about the fluting, I did that at soft leather before I put on the handles
Also the "electrician" won't be here tomorrow, mainly because I found out he's not an electrician.
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Having an electrician come out tomorrow to install the kiln circuit. Fingers crossed it turns out well.
I have a bunch of mugs I've been working on this week, trimmed, fluted and handled a few today, pulled more handles and will finish the rest up tomorrow, might even give the electric kiln a run if everything goes well!
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1 minute ago, jbruce said:
ok, I'll open up the bud box I have and send you a pic. I have to go to dinner first, but sometime soon. basically it's a 220v male connector on one side, a female 220v connector on the other. an ssr is mounted to the box with some thermal paste, and the rpi is plopped in there with a plastic case and a breadboard on top. I have not etched a circuit board for this and might not do so.
The bud box plugs into the wall, the kiln plugs into the bud box. simple.
That's perfect, because I will end up needing to bring it indoors when not in use (my kiln is outdoors under cover)
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Downramp is what I was thinking for slow cooling, that's great! Any tips on doing this project? Should I get a big kit box and mount the rpi in there and everything? The schematics look pretty simple as far as the circuitry goes, but it would be cool to see a shot of yours as well.
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Very cool, is there support for controlled cooling? Will be taking on this project as soon as I get the outlet for my kiln installed. Having an electrician over for a quote next Friday.
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4 minutes ago, neilestrick said:
Just so you have a point of comparison, I fired my E18T-3 yesterday, a fast bisque firing with a 4 hour preheat, and it averaged about 2,600 relay cycles per kiln section. These are typical mechanical relays. Because SSR's have a longer lifespan, it's okay to have them switch more, plus all that switching can increase element life. When relays switch less, the element has greater variation in temperature. That is, it heats up and cools down every time the relay turns it on and off. The longer the time period switched off, the greater the variation in the temperature of the element. As we know, metal expands and contracts as it heats and cools, and that movement decreases the life span of the element. By switching more often, the element can maintain a more constant temperature, which increases its life. So why don't all the manufacturers use SSR relays? Because they cost more, require an additional safety relay (even more cost), and most people don't care enough to justify the greater cost.
Interesting, thanks
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6 hours ago, Rae Reich said:
I think it's good that folks like JohhnyK were inspired to pot by Ghost and I'm sorry that it inspired some jerks to ogle. I didn't realize the depth of feeling it released in Real Potters to have their livelihoods made iconic.
I still love Patrick Swayze and Whoopie, so there's that.
I don't think it's because a movie made pottery iconic, I think it's because there's some kind of sensual overtone to the joke that comes with it. I don't even tell people I make pottery anymore because of it, even though it's a large part of my daily life. I get "ooo lah lah, like in ghost?" With winks and rapid eyebrow raises. I don't know what happens in ghost, but just from people's reactions there must have been something smutty or something. Makes me feel gross and uncomfortable.
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Just now, Bill Kielb said:
Nice on both fronts!
I was an electrician at age 20 (some time ago) and would offer to help but the distance from Wa to IL is rather significant. I will have to cheer you on from a distance. With respect to the Rpi I was going to drop you a note that said funny, now you have some programming to perfect along with your wares.
Sounds like a fun project, hope you can keep us apprised.
Will do, first step is saving up for the electrician. Luckily there will be less than a foot of wire to run, the kiln is just on the other side of the wall from my circuit breaker. After all is said and done will be nice not to blow 15 bucks in propane every time I bisque.
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Picked up a used kiln yesterday. Crucible 234, inside dimensions 23x18. It's a cone 10 electric with 3 inch brick. It needs new elements and two of the grooved bricks have chipped but overall good condition! The person I bought it from only fired to cone 06, so that's nice. The elements are functional but bulged in the bottom ring, might as well replace them if I'm going to have to pin them anyway, right?
Next step is getting the 50amp outlet installed outside, get a few bisques in, and then try making this raspberry pi controller. Not a bad kiln for 75 dollars I think. Anyone know a cheap electrician? Haha
I made some divided plates last week and my wife likes them so I'll make some more this week.
- GEP, Bill Kielb, Rae Reich and 1 other
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That's great, thanks for your cost list. Turns out I already have all of the stuff except the thermocouple module and the solid state relay and plugs. Should be cheap! Dangit now I have to do it!
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11,000 relay cycles, is that ok? How many cycles are they generally rated for? Might want to see if you can get away with floating average instead of being super precise. Is it because it was a slow firing with the elements crAnked to high? Surprised how cheap those relays are, this is something I'd like to do, where was the cost of 200 dollars to you?
Sorry for all of the questions, thanks.
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On 12/15/2018 at 8:20 AM, jbruce said:
I test fired my kiln with the new controller to 1000F last night. It included some fast ramps of 1200F/hour to 800F and from there 600F/hour to 1000F plus a soak of a few minutes. This was just to work out any glitches before I do a bisque fire. The software is configured to run every 2s and I grabbed some stats from that...
average error in degrees F 0.7665486726 solid state relay cycles 977 schedule length in hours 1.00 elements on (s) 1934.91 element percent on 53.75 element watts 9640 cost per kwh 0.126 schedule total cost $0.65 I'll pack the kiln today and bisque fire tomorrow. I'll post details after that.
How did it go? I'm very curious because I recently got a kiln with a kiln sitter and would like to do controlled cooling in the future. Am handy with programming and willing to learn the electronics, already have a pi
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9 minutes ago, glazenerd said:
Liam:
it might sound that way so perhaps I should add: I had no interest until my order arrived and I was hooked. Secondly, much has to do with my thirst to learn new things ( within limits.) I read dictionaries for leisure, I find them much more interesting than novels. Except of course for the old stuff..Steinbeck,Dickens, and Harper Lee.
So far the responses have been interesting insights.
I was being sarcastic, but I'm the same way. Natural curiousity is one of the greatest teachers.
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I was always exposed to ceramics from kindergarten on through college. Didn't have money for a wheel, kiln, clay, etc until my mid 30s where I am now. My recent inspiration was my neighbor who is a metal and woodworking artist, I told him I used to really enjoy ceramics and he said I should just do it. So I did.
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33 minutes ago, glazenerd said:
I was in a high end antique store in Williamsburg, Va. In 2007 admiring a Dresden vase. On the next table was a vase with floret looking shapes that caught my attention. The clerk had no idea what kind of glaze it was. I spent almost an entire year searching for a similar glaze: then one day I typed in " crystal glaze", because that was the appearance of it to me. The first website was William Melstrom from Texas; lo and behold I had been looking at crystalline glaze. I had no prior experience with or interest for that matter in pottery, although I did help my wife glaze bisq ware some 20 years prior.
After doing some research, I ordered the kilns, rollers, and sundry items required to make this speciality glaze. So I jumped into the rabbit hole from the outset, and here I am ten years later. I noticed early on that crystals formed differently on different clay bodies; although I made no changes in recipe. Those differences lead to extensive research over the last five years trying to understand why. And now I know why.....
Tom
Sounds more like an journey of self-punishment. I thank you for your sacrifice though, I've learned more than a little from your explorations posted here on the forums.
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Welllllllllp, I ended up having time to go get clay over the weekend. Picked up 500lbs, as well as some glaze chemicals I wanted. I threw a big 15lb moon jar out of recycled clay last night, wow what an experience! It was probably a little softer than I should have thrown with but it was a lot of fun and great practice for throwing bigger. My new goal is to center and throw a 25 pounds vessel which is I think the max my rk2 is rated for. I probably won't be able to fire a piece that big without modifying my kiln, but I guess it's a personal challenge. Anyhow, with all of this brand new clay in my hands I need to get busy throwing some real stuff too. Bowls, bowls, bowls.
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Geeks only - Raspberry PI controlled kiln
in Equipment Use and Repair
Posted
So what's the solution to the single ssr? Two separate ssrs connected to the rpi? Does the rpi have two outputs to trigger the ssrs?
I looked at 2 pole ssrs and they're nutty expensive, used in HVAC it looks like